I don't think we will ever see that level of efficiency, cleanliness and safety in established US cities. The culture is different. More importantly, I think, is that US cities have a skeleton which is generally not conducive to the transportation network seen in Japan.
I think that the current push in the US to add ADUs('granny flats') in suburban neighborhoods will show us the limitations of our current layouts. Cramming more density into an infrastructure limited area will likely result in lower quality of life. The solution, IMHO, is to undertake larger projects where entire neighborhoods are bought out at fair price(at huge public expense) and redeveloped according to modern urban design patterns. That will likely never happen due to the obsession with the past and unwillingness to allow change.
You can't prove this on small scale though, good transit is about the places you can get to: the jobs, stores, churches, restaurants, friends, and whatever else you might want to do in your city. A fast bus (not to be confused with the typical slow meandering buses most people are used to) every 5 minutes that doesn't connect to any other buses is useless. A bus every 10 minutes that via affordable transfers to anywhere can get you anywhere can get good use. Plumbers and the like still need to drive, so private autos will still be 30% of all trips, but a good transit system can be useful in the suburbs if you can just get there.
Did you note I stuck affordable in there? The ideal transit system should have the majority of the riders on a monthly unlimited rides family pass.
The main problem with that is that it's still not worth it in most cases. For most neighborhoods there's nothing to walk to because the population density is too low to support businesses or services. There's too much fragmented farmland separating out all the little pods of cookie cutter houses and strip malls, so the only configuration that works is to have a little pod of commercial at some highway intersection while all the residential to support that is sprinkled around a 10 mile radius of fragmented development.
So in Japan, you have many neighborhoods that have a house beside a tea shop beside a tailor beside house. In the US, it is very rare to find such mixes.